Cleaning compositions have been commercially produced for many specific cleaning purposes. The intended surface and soil conditions often dictate the composition of the cleaner. The cleaners have been produced in both liquid and granular form, and have been formulated to perform specific cleaning tasks. For example, cleaners have been produced to clean tile floors in the kitchen or bathroom, porcelain or ceramic sinks, stainless steel, glass, painted surfaces and plastic laminates. In general, the different surfaces require specific cleaning compositions for each surface to be cleaned and it has proven difficult to produce an all purpose cleaner that is equally effective on all surfaces.
One of the more common soils in kitchens and bathrooms is soap scum formed by the reaction between a weak fatty acid and a soluble calcium salt. The calcium is typically provided in the water while the fatty acids are supplied by the soap. The insoluble fatty acid calcium salt can be removed using a detergent with a sequestering agent to form a calcium adduct that is more stable than the calcium soap. The formation of the calcium adduct is generally favored by a high pH with a calcium chelating agent. Alternatively, soap scum can be removed by an acid that is stronger than the fatty acid. The effectiveness of the reaction is generally related to the strength of the acid used for displacement of the scum.
Numerous commerically available cleaning agents have been developed to cope with and remove soap scum from kitchen and bathroom surfaces. The more effective cleaning agents include a sequestering agent such as ethylenediaminetetraacetic acid (EDTA), nitriloacetate (NTA) or N(2-hydroxyethyl) immodiacetate (HEIDA). Other cleaning formulations utilize phosphates or organic solvents to increase the cleaning effectiveness of the composition. While many of these cleaning compositions may be effective in removing soap scum, not all of the compositions are suitable for all surfaces. For example, acidic cleaning compositions cannot be used on acid-sensitive surfaces such as marble, limestone and some tiles. Other cleaning compositions that are sufficiently alkaline so as to be suitable for cleaning acid-sensitive surfaces suffer from the disadvantage of containing phosphate components. In recent years there has been increased public awareness that phosphates, as well as other components in cleaning compositions, are harmful to the environment, which has led to the development of phosphate-free detergents and cleaning compositions.
One example of a phosphate-free cleaning composition is disclosed in U.S. Pat. No. 4,349,447. The cleaning composition, as disclosed, includes an anionic or nonionic synthetic surfactant and an effective amount of a salt of imido-bis-sulfuric acid, palmitic acid and a carboxylic acid salt of N,N,-bis(carboxymethyl)glutamic acid or N,N-bis(carboxymethyl) phenylalanine. The imino-bis-sulfate is reported to have a very high pH buffering action and proper chelating ability. The palmitate is reported to have a high ability for sequestering calcium and magnesium ions and the ability to lower the zeta potential of the surfaces of dirt and fibers.
U.S. Pat. No. 3,959,165 relates to a biodegradable laundering detergent composition including a higher alkane sulfonate synthetic organic detergent, a nonionic detergent, a high C.sub.10 -C.sub.18 fatty acid soap, sodium silicate and a carbonate. Sodium carbonate is disclosed as the main alkalizer and builder in the composition. The detergent composition is produced as a dry pulverulent material. The composition is primarily used as a laundry detergent and is not suitable as a cleaner for removing soap scum and grease soils from hard surfaces.
U.S. Pat. No. 4,486,329 relates to a single phase, liquid cleaning composition for hard surfaces. The disclosed composition includes a water-soluble mono, di, or triethanolamine or ethylenediamine salt of an anionic sulfated or sulfonated detergent, a water-soluble alkyleneoxylated nonionic detergent and a water soluble ethanolamine or ethylenediamine salt of a lower alkyl monocarboxylic acid. The cleaner is disclosed as an all-purpose cleaner with reduced streaking without rinsing.
The European Patent Application No. 317,542 relates to a hard surface cleaning composition containing an organic solvent and an iminodiacetic acid derivative and particularly N-glyceryl-imino N,N-diacetic acid. The disclosed organic solvents include alkyl benzene sulfonates, paraffin sulfonates, and ethoxylated alcohols. The cleaning composition is disclosed as having good soil-removing properties from hard surfaces.
The European Patent Application No. 105,063 relates generally to a hard surface cleaner containing a non-soap surfactant, a polyphosphate or polyphosphonate sequestering agent and an organic solvent. The preferred organic solvent is diethylene glycol mono-n-butyl ether. The cleaning composition is disclosed as being suitable for cleaning floors, greasy walls and bathtub soils when used at full strength. This composition has the disadvantage of relying on the use of phosphates as a sequestering agent, which reduces consumer acceptance of the product.
Some of the above-noted cleaning compositions have not been entirely effective in removing soap scum from bathroom and kitchen hard surfaces. Many of the previous cleaning compositions that have been used heretofore are fairly effective in removing soap scum but have the distinct drawback of utilizing phosphates or other chelating agents that are not readily biodegradable. The present invention is directed to a novel hard surface cleaning composition which overcomes the drawbacks of the previously-used cleaning compositions.